whois 172.18.0.1

% This is the dn42 whois query service.

% Information related to 'inetnum/0.0.0.0_0':
inetnum:	0.0.0.0 - 255.255.255.255
cidr:	0.0.0.0/0
netname:	NET-BLK0-DN42
policy:	reserved
descr:	* The entire IPv4 address space
mnt-by:	DN42-MNT
status:	ALLOCATED
source:	DN42